Induced symbiotic osmosis [ISO] for salinity power generation

Abstract

A method comprising providing a power train comprising a plurality of cells, each cell forming a hydraulic loop; producing a power train cycle comprising a controlled concentration-pressure loop wherein the concentration field: (a) osmotically induces a continuous and constant flow rate of substantially salt-free permeate flux throughout the power train; (b) maintains a salt concentration difference across the semipermeable membrane shared by the adjacent cells in the plurality of cells; (c) defines a salt concentration ratio within each cell that ensures a net positive power generation; and, (d) discharges the concentrated brine at the opposing end cell; and operating the power train under conditions effective to generate net positive power at an efficiency of 35% or more.

I claim: 
     
       1. A method comprising:
 providing a power train comprising a plurality of cells comprising an initial end cell, one or more intermediate cells, and an opposed end cell, each cell in the plurality of cells forming a hydraulic loop configured of specified volumetric and flow capacity for a specified permeate flux, each cell in the plurality of cells also having a pumping system and a hydro-power generation turbine system, wherein adjacent cells in the plurality of cells share a semipermeable membrane; 
 charging each cell in the plurality of cells with a given brine having a specified ionizable inorganic salt concentration and type, without permitting mixing of the given brines among the adjacent cells in the plurality of cells, creating a gradient of salt concentration and resulting osmotic potential that progressively increases stepwise from the initial end cell, across the one or more intermediate cells, to the opposed end cell; 
 feeding to the power train an initial brine comprising low to no salt concentration water at the initial end cell, producing a concentration field across the plurality of cells comprising a progressively increasing concentration and osmotic pressure ratio bounded by water of low to no salt concentration at the initial end cell and by a concentrated brine at the opposed end cell, thereby producing a power train cycle comprising a controlled concentration-pressure loop wherein the concentration field: (a) osmotically induces a continuous and constant flow rate of substantially salt-free permeate flux throughout the power train; (b) maintains a salt concentration difference across the semipermeable membrane shared by the adjacent cells in the plurality of cells; (c) defines a salt concentration ratio within each cell that ensures a net positive power generation; and, (d) discharges the concentrated brine at the opposing end cell; and 
 operating the power train under conditions effective to generate net positive power. 
 
     
     
       2. The method of  claim 1  comprising charging to the initial end cell a given brine comprising a salt concentration that is two or more times the solubility of sodium chloride. 
     
     
       3. The method of  claim 1  comprising charging to the initial end cell a given brine having a salt concentration of about 4% or more, when using freshwater as the initial brine. 
     
     
       4. The method of  claim 2  further comprising:
 (a) collecting and concentrating the concentrated brine discharged at the opposed end cell, producing a further concentrated brine; and 
 (b) recycling the further concentrated brine to the opposed end cell. 
 
     
     
       5. The method according to  claim 1  wherein the given brine is selected from the group including hyper saline water, salt pond water, salt dome wash water, rejected brine from water recovery by reverse osmosis, evaporation, distillation, and a formulation of dissolved ionizable salt solutions. 
     
     
       6. The method according to  claim 1 , wherein the semi-permeable membrane is selectively-permeable to water but impermeable to solute. 
     
     
       7. The method according to  claim 1 , wherein the concentrated brine circulates toward the pump system in the plurality of cells and fluid having a lower salt concentration than the concentrated brine circulates toward the hydro-power generating turbine system in the plurality of cells, producing a ratio within each cell of higher than 2.0 based on (a) concentrated brine to (b) fluid having a lower salt concentration than the concentrated brine. 
     
     
       8. The method according to  claim 1 , wherein the given brine comprises an amount of hydrate inhibitor. 
     
     
       9. The method according to  claim 1  wherein the specified ionizable inorganic salt type is selected from the group consisting of chlorides of sodium, magnesium, and calcium. 
     
     
       10. The method according to  claim 1 , wherein:
 maintaining the continuous and constant flow rate of substantially salt-free permeate flux increases the volume of pressurized brine in the plurality of cells, thereby increasing a rate of free energy in the plurality of cells; and, 
 the net positive power is generated by passing increased-volume pressurized brine through the hydro-turbine system, the net positive power for each cell in the plurality of cells comprising the rate of change of free energy in the respective cell. 
 
     
     
       11. The method according to  claim 1 , wherein the given brine of the initial end cell has no direct contact with the given brine of the opposed end cell. 
     
     
       12. The method according to  claim 1  wherein the pumping system transfers to a downstream adjacent cell a reduced-volume concentrated brine discharged from the hydro-turbine generation system. 
     
     
       13. The method according to  claim 1 , wherein the plurality of cells cycle continuously in the same pattern maintaining countercurrent flow across each semi-permeable membrane and wherein an interruption of a segment of the power train halts the flow of the substantially salt-free permeate flux.